Piezocrstal device of the sealed type



Dec. 17, 1946. C, F DAUSMANN 2,412,719

PIEZO-CRYSTAL DEVICE OF THE SEALED TYPE I l Filed May 5, 1944 frA ATTORN EY i3 may be so formed thuat as the nuts li are tightened salario Cover plate s may be recessed to seat the nuts i3 which engage the threaded bolts li. The nuts they can only be tightened or loosened with a special tool, 4thus preventing the'removal o the cover plate il with an ordinary screw-driver or other common tool.

The piezo-electric-crystal unit having been loaded into the cavity i5, and the spacer il placed above it, the gasket l which may be oi any suitable material such as neoprene, or rubber, is placed in proper position, and the openings in the metal cover plate 3 are then brought into registry `with the threaded bolts ll and the nuts itl are drawn tight, it being understood that gasket 2 has openings to accommodate bolts li.

yThe sealing edge i2 bites into ,the gasket ii,

against the Bakelite cover plate 5. I have found that in sorne cases Where the sealing rib i2 only is used, that the pressure on plate 3 by nuts i3 necessary to effect sealing may cause the said plate il to bow upwardly as indicated by the dotted line (Figi), thus reducing the eiectiveness of the seal. However by using the auxiliary members iii the more tightly the cover plate 3 is bolted down against the surface of the end wall of the housing l the tendency of plate ii to bow is obviated and the more elcient `:vill be the seal formed between the sealing edge l2, the gasket 2, and the cover 'plate t, l

Fig. 5 diagrammatically illustrates the location and directionof the several forces acting upon the cover plate 3, from which it will be seen that the beads lil act as ulcrums to prevent upward bowing ci plate 3, as the nut-s lil are tightened.

The protuberances it may be arranged at suitably spaced intervals, or they may ce so spaced as to deiine the rib sections lf2-ld (Fig. 6), arranged in spaced relation to the sealing edge i2 and the threaded bolts il. The beads lil or the rib sections iiild may be slightly higher than the sealing edge i2. This particular construction enhances the enciency of the seal, and produces f a very efficient dust-proof and moisture-proof housing. Various changes and modifications may be made in the illustrated embodiments Without departing from tne spirit and scope ci the invention thus instead ci providing the continuous sealing rib i2 on the housing it may be provided on plate 3, and likewise for the members lil and ifi. ii desired, the auxiliary rib may completely surround rib l2 in spaced relation thereto, to provide space for the bolts i l.

What is claimed is:

i. A piezo-crystal device comprising a housing naving a cavity to receive a piezo-crystal unit, a sealing edge for the open end of said cavity, a projection adjacent to said sealing edge, a sealing 'closure for said cavity, means for fastening said closure against said sealing edge,`said pro- `jection cci-operating with said fastening means to increase the emciency of the seal between the closure and the scaling edge.

2. A ypiezo-crystal device comprising a housing having a cavity to receive a piezo-crystal unit, the open end of said cavity forming a seat fora cavity closure member, a rib projecting above the surface of said seat and surrounding said cavity t0 form a sealing edge,a projection formed on said seat adjacent to said rib, a closure adapted to register with said seat and to engage said projection, and means for forcing said closure against said rib, said projection engaging the rim oi the closure to increase the efficiency o the seal between the rib and the closure.

3. A piezo-crystal device comprising a housing having a cavity. to receive a piezo-crystal unit, the open end o said cavity forming a seat for a gasket, a sealing edge formed in and adjacent the inner edge of said seat, a projection formed in said seat outside said sealing edge, a closure operable under pressure to press a gasket against said seat, and means for applying pressure to said closure whereby said-projection engages the rim of said closure to increase the eciency oi the seal formed between said sealing edge, a gasket, and said closure.

4. A piezo-crystal device comprising a housing having a cavity to receive a piezo-crystal unit, the open end `of said cavity forming a seat for a closure for said cavity, a rib projecting above the surface of said seat to form a sealing edge, a projection formed in said seat adjacent to said rib, said projection extending above the crown of said rib, a closure adapted to register with said seat and to engage said projection, and means for applying pressure to said closure against increasing counter-pressure exerted upon the edge or" said closure by said projection,

device comprising a housing a piezo-crystal unit,

eiciency ci the seal -formed by said sealing edge, y

said gasket, and said closure.

6. A housing for a piezo-crystal unit having at least one end open to receive a crystal unit said one end having an integrally formed sealing edge surrounding the open end adjacent the inner periphery, and a plurality or auxiliary sealing edges in spaced relation to the nrst edge for the purpose set forth.

CHARLES F. DAUSMANN.

to increase the eiicienc'y of the seal formed by said sealing edge 

